The SECRET HACK supermarkets hope you never try

Easy supermarket-to-garden hacks

Simon A. Croy demonstrates four simple ways to regrow or grow supermarket ingredients at home so you can harvest fresh herbs, greens and spicy leaves quickly.

Spring onions

• Cut off and use the edible top, leaving the root stub — don’t throw the roots away.
• Plant the rooted base in compost in a container with drainage holes; press in gently so only the stub tip is above the compost.
• Water every 2–3 days. New growth appears in about 7–10 days.
• You can repeatedly harvest by cutting back; they will regrow for many cycles.

Mint

• Take sprigs/cuttings from a supermarket mint packet.
• Remove lower leaves and cut just below a node (where roots form).
• Root in a glass of water on a sunny windowsill (roots in ~7–10 days) or plant directly into compost.
• Grow mint in containers only — it spreads aggressively if planted directly in the ground.
• Plant different mint varieties in separate pots to create a flavorful patio herb collection for salads and cocktails.

Chia seeds (microgreens)

• Line a plate with damp kitchen paper/kitchen roll.
• Evenly sprinkle chia seeds over the damp paper.
• Keep the paper moist on a windowsill; water every couple of days.
• Cut microgreens with scissors after a few days up to two weeks and add to salads, sandwiches, or smoothies.

Mustard

• Fill a pot with compost and sprinkle supermarket mustard seeds on top (yellow or black).
• Cover lightly with compost and water.
• Leaves grow quickly — use the spicy mustard leaves in salads.
• Allow plants to flower and go to seed if you want to collect seeds for homemade mustard.

General tips

• Use any recycled container with drainage holes (for example, supermarket plastic trays).
• A sunny windowsill or sunny patio is ideal.
• Trim long roots if needed; reduce leaves on cuttings to limit water loss while rooting.
• Plant multiple cuttings/seeds to increase your success rate.
• Most of these will be harvestable in about 1–2 weeks if kept watered and sunny.

Notable speaker and sources

• Speaker: Simon A. Croy
• Items referenced: supermarket spring onions, mint packets, chia seeds (for microgreens), mustard seeds, compost, kitchen roll, recycled containers
• Associated video: BBC Gardener’s World magazine